Onthophagus kokodentatus Krikken & Huijbregts

Krikken, J. & Huijbregts, J., 2013, New Guinea Onthophagus: taxonomy of ten small, unicolored new species (Coleoptera: Scarabaeidae: Scarabaeinae), Zootaxa 3619 (5), pp. 501-525 : 514-515

Onthophagus kokodentatus Krikken & Huijbregts , new species

( Figs. 10, 21 , 74–79 )

Type material. Holotype male (CMNC) from PNG: Iora Creek, 17 km S Kokoda, Kokoda Trail, 1400 m, 3- 6.viii.1976, O. Kukal, carrion, montane rainforest. Paratypes listed in Appendix 1.

Diagnosis. Clypeal apex bidentate; major males have their denticles set on a reflexed lobe (emargination between denticles not going down to base of lobe), this lobe on either side delimited by a sinuate border (contrary to O. dissidentatus ). Clypeus and frons in both sexes without any further protrusions (contrary to O. dissidentatus ). Onthophagus kokodentatus usually shiny black (occasionally with metallic lustre); most of dorsum distinctly, finely punctate, punctation varying in strength. Eye foramina narrow. Pronotum entirely evenly convex, lateral and basal borders evenly, widely rounded. Proximal serrate section of protibia long (8–10 very small denticles). Pygidium simply punctate. Body length usually 3.5–4.5 mm.

Description (holotype, male). Body length approximately 4.5 mm. Habitus convex, dorsum slightly deplanate. Color largely black, shiny; legs dark brown. Dorsum glabrous, apart from microstubbles in fine punctures, underside with numerous pale-yellow setae; dorsal punctation generally fine, evenly scattered, sparse to abundant, denser on head; vague micropunctation present.

Head shiny black. Clypeal border widely, evenly rounded to paramedian sinus, delimiting bidentate lobe; clypeofrontal surface evenly, abundantly to densely, distinctly punctate; clypeogenal transition almost continuous at border; clypeogenal suture very fine; clypeofrontal disc slightly convex, without elevation. Genal surface finely, abundantly punctate, border finely marginate, straight in front, lateral tip widely rounded. Vertexal delimitation convex. Eye foramina very narrow, with approximately 7 facet rows across widest point. Ratio interocular distance / maximum eye width 6.5–7.0.

Pronotum black, shiny, moderately, evenly convex (lacking midline impression); anterior declivity gradual, unmodified; surface abundantly, evenly, finely, distinctly punctate throughout, micropunctation hardly distinct; anterior and lateral borders finely marginate; base very finely marginate; lateral border entirely widely evenly rounded to posterolateral edge (full-face and dorsal views), anterolateral angle shortly rounded, slightly obtuse; posterolateral angle fully rounded off to widely rounded basal border.

Elytra black, shiny; scutellum indistinct, shape of base and apex unmodified; epipleuron glabrous, brownblack, shiny, with some very fine, scattered punctures. Elytra broad, with 8 straight to slightly curved, fine but distinct striae; stria 7 evenly, very slightly curved in front, ending at humeral umbone; strial punctures very fine, mostly separated by 5–8 puncture diameters, finely crenulating interstriae. Interstrial surfaces slightly convex, scattered with sparse to abundant, very fine punctation.

Antennal club yellow, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus concave, posteriorly delimited by simple coxal-marginal ridge reaching lateral border. Propectoral sides with numerous seta-bearing punctures. Metasternum shiny, anterior lobe very slightly prow shaped in front; metasternal lobe and disc densely, finely punctate, posteriorly with shallow midline impression, micropunctate; metasternal flanks with numerous punctures (most with shorter setae). Abdominal ventrites moderately shiny (slightly sericeous), each laterally with row of (irregularly annulate) seta-bearing punctures. Pygidium shiny black, glabrous; base with transverse ridge, apex finely marginate; surface evenly convex, with dense, fine but distinct, simple punctation.

Legs generally shiny brown. Protibia robust, with 3+1 larger external denticles (distal 3 larger, acuminate, proximal denticle very small), separated by some serration; proximal serration consisting of 8–9 fine denticles; apico-external denticle long, slender, oblique to tibial axis; apico-internal angle unmodified, terminal spur small, elongate-acuminate, slightly curved; protibial underside with low longitudinal crest; protarsus slender. Profemur robust, underside shiny, with few seta-bearing punctures and numerous fine punctures. Mesofemoral and metafemoral undersides similar to profemora, but with less setae. Mesotibiae and metatibiae slender, dilated distad to transversely subelliptic crest, which is fringed with short fossorial spines below, and some long, fine spines above; externally with approximately 3 very slight, spine-bearing fossorial protrusions. Mesotarsi and metatarsi generally very slender, with very fine claws; mesotarsomeres and metatarsomeres 1 long, almost straight, unmodified, shorter than 2–5 combined. Terminal spurs on mesotibiae and metatibiae slender, elongate-acuminate. Length proportions terminal spur // metatarsomeres 1–5 in approximate integers: 10// 10/5/3 /2/4 (male paratype; holotype missing some tarsomeres).

Parameres broad, humped, tip bent downward, Fig. 21 .

Measurements in mm (dorsal view). Maximum width of head 1.3. Median length of pronotum 1.4, maximum width 2.2. Sutural length of elytra 2.1, maximum width combined 2.5.

Variation and sexual dimorphism. Male bidentate lobe varies, being long, strongly reflexed in major males; female clypeal apex bidentate, but not extended into strongly reflexed lobe. Head surface in both sexes without protrusions. Color mostly black, but occasionally with metallic lustre. Clypeal surface of female rugulate-punctate. A small series from Wau has a greenish-metallic pronotum, and a less pronounced dorsal punctation; included in this species on account of their very similar parameral shape.

Etymology. Name is a contraction referring to both type locality and dentate clypeus.

Figures

FIGURES 13 – 24. Parameres (lateral view) of Onthophagus species. 13, O. acerus, holotype; 14, O. aceroides, holotype; 15, O. baiyericus, holotype; 16, O. daymanus, holotype; 17, O. kokopygus, holotype; 18, O. kokocellosus, holotype; 19, O. bituberoculus, holotype; 20, O. kukali, holotype; 21, O. kokodentatus, holotype; 22 – 23, O. dissidentatus, paratype, Wau (22), paratype. N Port Moresby (23); 24, O. ofianus, holotype. Scale lines (on top of relevant parameres) equal 0.5 mm.

FIGURES 74 – 91. Onthophagus species, body parts. 74 – 79, O. kokodentatus, holotype (73 – 78), female paratype Iora Creek (79); 80 – 85, O. dissidentatus, holotype (80 – 84), female paratype N Port Moresby (85); 86 – 91, O. ofianus, holotype (85 – 89), female paratype Manari (91). Head (full-face) 74, 79, 80, 85, 91; pronotum (dorsal) 75, (dorsal, with rear view of frontovertexal protrusions) 81, 87; left elytron (dorsal) 76, 82, 88; protibia (upper side) 77, 83, 89; metatibia (underside) 78, 84, 90. Scale lines equal 1 mm.